The invention relates to an electric cable protective pipe. According to the structure, a protective pipe body comprises two pieces of semi-cylindrical pipes, the two sides of the pipe wall of each piece of pipe are respectively provided with a right angular U-shaped plate, threaded holes are formed in the U-shaped plates, and the threaded holes are fastened through bolts. Arc plates are arranged on the outer surface of the protective pipe, the radian of the arc plate is matched with the protective pipe, and the U-shaped plate is fastened to the protective pipe through the arc plates. Regarding the situation that protection needs to be increased on site, the flexible, convenient and practical superiority is fully expressed, the protective pipe can be added and disassembled at will at the places where protection needs to be increased, particularly the middle section on which electric cables are already laid. In addition, the electric cable protective pipe can be widely applied under the condition that the electric cables need to be contemporarily laid across a road, the semi-cylindrical protective pipe is directly fixed to the ground through expansion screws, the effect of preventing the vehicles from pressing the electric cables is well achieved, and cost for original overhead laying or burying laying is greatly saved.